A miniaturized four-port multiple-input multiple-output (MIMO) antenna for ultra-wideband (UWB) applications is presented. The proposed UWB MIMO antenna has a compact size of 34 × 34 mm2. Four antenna elements are placed orthogonally, and the element is connected to the feed line through metal vias in the substrate. These metal vias increase the bandwidth of the high frequency part of the antenna. A T-shaped slit, a rectangular slit, and a triangular chamfer are etched on the ground between two adjacent antenna elements. The working bandwidth of the antenna is 2.5-11.6 GHz, covering the entire UWB application band. The isolation between antenna elements is more than 18 dB within the operating bandwidth. Details of the design methodology and results are presented and discussed. Envelope correlation coefficient is computed, and it is within the acceptable limit, which validates the design concept for building a compact MIMO antenna system with good performance.
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